Generally, a drum-type washer performs a washing operation using a frictional force between a drum rotating by a driving force of a motor and laundry articles and a dropping impact of the laundry articles in a state where a detergent, washing water and the laundry articles are loaded in the drum. In the drum-type washer, there is little damage on the laundry articles, the laundry articles are not tangled with each other, and a washing effect of beating and rubbing can be provided.
Compared to the drum-type washer, a pulsator-type washer includes a water-extracting tub in a water tank which stores the washing water. In the pulsator-type washer, a washing operation is performed in a state where the laundry articles are soaked in the washing water supplied into the water-extracting tub, thereby consuming a large amount of water.
In the pulsator-type washer, the washing operation is performed by action of a detergent and friction between the washing water and the laundry articles due to the rotation of the water-extracting tub or the rotation of a pulsator disposed at a lower portion of the water-extracting tub to form water current.
That is, in the drum-type washer, a rotation shaft of the drum is formed substantially parallel to the ground. Accordingly, even when a small amount of washing water is stored in the tub and the drum, the washing operation is performed by dropping of the laundry articles. However, in the pulsator-type washer, a rotation shaft of the water-extracting tub is formed substantially perpendicular to the ground. Accordingly, only when the washing water is supplied such that the laundry articles are soaked in the washing water, the washing operation can be performed.
Meanwhile, in a conventional pulsator-type washer, the washing water is always full to an upper portion of the water tank. The filling of the water tank is repeated every time the washer is operated.
High efficiency, drum-style, front-load washing machines are designed to use less water, less energy and high efficiency detergent. If, contrary to the manufacturer's instructions, the operator of the washing machine regularly uses regular detergent, rather than high efficiency detergent, or regularly uses more than the recommended amount of high efficiency detergent and if the operator does not perform the regular maintenance recommended by the manufacturer, it is possible that excessive volumes of suds and foam may result and that this may lead to the accumulation of undissolved detergent and soil inside the washing machine. The accumulation of undissolved detergent and soil inside the washing machine due to misuse may lead to development of mold which can in turn produce an odor that some perceive to be unpleasant.
In this case, since the water tank is not operated, contaminants or fur may be deposited on the lower portion and the inner peripheral surface of the water tank. Further, as time goes by, the contaminants or fur may be decomposed, thereby generating an offensive smell or contaminating the laundry articles.
Thus, in the conventional pulsator-type washer, various methods have been proposed to clean the inner peripheral surface of the water tank. However, in a state where the water tank is filled with the washing water, it is uneasy to clean the water tank by the fast flowing water generated by rotating the water-extracting tub at a high speed without using an additional device for the following reason.
In the high-speed rotation of the water-extracting tub, a large load is exerted on the motor due to the frictional force between the washing water and the outer surface of the water-extracting tub. Even when the water-extracting rotates at a high speed, it is difficult that the washing water reaches the upper inner peripheral surface of the water tank.
Thus, in the conventional pulsator-type washer, a special detergent is used to clean the water tank by action of the detergent in a general washing or rinsing operation.
However, generally, the detergent for cleaning the water tank has a large amount of chemical components for a strong cleaning force, which cause water pollution, differently from the detergent for washing. Accordingly, the detergent for cleaning the water tank is not friendly to the environment.
FIG. 1 is a diagram showing a schematic configuration of a general drum-type washer. The general drum-type washer is described with reference to FIG. 1.
As shown in FIG. 1, the drum-type washer includes a cabinet 1 having a laundry loading port formed on its front surface, a door 2 installed on the laundry loading port of the cabinet 1 to open/close the laundry loading port, a tub 10 installed in the cabinet 1 to store the washing water therein, a motor 4 installed at the tub 10 to generate a drive force, a washing shaft 5 connected to the motor 4, and a drum 6 connected to the washing shaft 5 to wash laundry articles by the drive force transferred from the motor 4.
The tub 10 is supported by a damper 11 and a spring 23. The damper 11 and spring 23 serve to absorb the vibration generated in the rotations of the motor 4 and the drum 6.
The motor 4 includes a rotor (not shown) and a stator (not shown).
In the drum-type washer having the above configuration, the washing water is supplied such that only lower portions of the tub 10 and the drum 6 are soaked in the washing water differently from the pulsator-type washer. Further, only a portion of the washing water stored in the lower portion of the tub is lifted up with the washing water by a lifter (not shown) provided in the drum and then dropped.
Accordingly, in the drum-type washer differently from the pulsator-type washer, opposite side portions and an upper portion of the inner peripheral surface of the tub are not soaked in the washing water.
Thus, in the conventional drum-type washer, it is not considered that the contaminants or fur may be accumulated due to misuse on the opposite side portions of the inner peripheral surface of the tub, particularly, on the upper portion of the inner peripheral surface of the tub. Accordingly, it is not required to clean the contaminants deposited on those positions.
Meanwhile, although a term of “tub cleaning” is used in the conventional drum-type washer, the term of “tub cleaning” does not mean the cleaning of the opposite side portions of the inner peripheral surface of the tub, particularly, on the upper portion of the inner peripheral surface of the tub. That is, it means cleaning of only the lower portion of the inner peripheral surface of the tub.
However, applicants of the present invention found the fact that the contaminants and fur are accumulated due to misuse on the opposite side portions and an upper portion of the inner peripheral surface of the tub as well as the lower portion thereof, thereby generating an offensive smell or contaminating the laundry articles.
Therefore, it is required to find a method for easily cleaning the entire inner peripheral surface of the tub without using an additional device for cleaning the tub.